AVS 66th International Symposium & Exhibition
    Electronic Materials and Photonics Division Monday Sessions
       Session EM+PS+TF-MoA

Paper EM+PS+TF-MoA6
Interfacial Charge Engineering in Ferroelectric-Gated Mott Transistors

Monday, October 21, 2019, 3:20 pm, Room A214

Session: New Devices and Materials for Logic and Memory
Presenter: Xia Hong, University of Nebraska-Lincoln
Authors: XG. Chen, University of Nebraska-Lincoln
Y. Hao, University of Nebraska-Lincoln
L. Zhang, University of Nebraska-Lincoln
X. Hong, University of Nebraska-Lincoln
Correspondent: Click to Email
Ferroelectric field effect transistors (FeFETs) built upon Mott insulator channel materials have been intensively investigated over the last two decades for developing nonvolatile memory and logic applications with sub-nanometer size scaling limit. However, the intrinsically high carrier density of the Mott channel (1022-1023/cm3) also imposes significant challenges in achieving substantial modulation of the channel conduction. In this work, we exploit the intricate interplay between interfacial charge screening and transfer effects in epitaxial heterostructures composed of two strongly correlated oxide layers, one layer of rare earth nickelate RNiO3 (R = La, Nd, Sm) and one layer of (La,Sr)MnO3 (LSMO), to realize a giant enhancement of the ferroelectric field effect in Mott-FeFETs with a Pb(Zr,Ti)O3 gate. For devices with 1-5 nm single layer RNiO3 channels, the room temperature resistance switching ratio (Roff-Ron)/Ron increases with decreasing channel thickness till it reaches the electrical dead layer thickness. For devices built upon RNiO3/LSMO bilayer channels, the resistance switching ratio is enhanced by up to two orders of magnitude compared with the single layer channel devices with the same channel thickness. Systematic studies of the layer thickness dependence of the field effect show that the LSMO buffer layer not only tailors the carrier density profile in RNiO3 through interfacial charge transfer, but also provides an extended screening layer that reduces the depolarization effect in the ferroelectric gate. Our study points to an effective strategy for building high density nanoelectronic and spintronic applications via functional complex oxide heterointerfaces.